CD28 and pulmonary arterial hypertension: Without PAH stimulation, anti-CD3/CD28-activated T cells from AA patients exhibited higher expression of the master Th17 transcription factors RORC and of the AhR target gene CYP1A1 than NA subjects, which were associated with increased levels of IL-17A, IL-17F and IL-22 cytokines, suggesting that AA patients might display a higher sensitivity to the induction of the Th17/Th22 profile than NA subjects after polyclonal activation.